Centrifugal blower, pump, compressor, &amp;c.



H. KELLER. GPNTRIPUGAL BLOWER, PUMP, COMPRESSOR, am.

APPLICATION FILED NOVJZ'T, 1907.

Patented July 4, 1911.

Inventor". Huldreic Kel ler,

Witnesses:

arnnfr time.

HULDREICH KELLER, F BERLIN, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPQRATION OF NEW YORK.

CENTRIFUGAL BLOWER, PUMP, COMPRESSQR, &C.

Specication of Letters Patent.

ascesa.

Application filed November 27, 1907.

To all 'whom'fzlt may concern:

Be it known that I, HULDREICH KELLER, a citizen of Switzerland, residing at Berlin, Germany, have invented certain new and useful Improvements in Centrifugal Blowers, Pumps, Compressors, &c., of which the following is a specification.

The present invention relates to centrifugal blowers, pumps, compressors, etc., and more especially to those having' an impeller with a uni-lateral inlet and rotating at high p speed.

f-packings, etc.,

In such an apparatus when operating there is an ultimate accumulation of pressure on one side of the impeller which exerts a longitudinal thrust on the shaft that is highly objectionable. y

My invention has for its object to provide means for equalizing the pressures on opposite sides of the impeller to avoid the thrust, and this without unduly weakening the structure on one hand or making it excesy sively heavy on the other. Y

In the accompanying drawing, which shows structures illustrative of the invention, Figure l. is an axial section of a centrifugal pump with a part of the casing broken away; Fig. 2 isaJ sideV elevation of the impeller; Fig. 3 isa sectional view of a modification showing a spiral groove in the impeller` hub for equalizingpressures; and

igs. 4 and 5 are views showinggrooves similar to that of Fig. l.

l indicates4 the high-speed shaft of a pump, yand 2 the inclosing casing having a conduit 3 that is connected t-o the system receiving iuid'from the pump. The bearings, havepbe'en -omitted for the sake of clearness.

an impeller 4 of the uni-lateral inlet type.

l 5` seated 1n his impeller is secured to the' shaft by a key a groove in the shaft and also fin a comparatively shallow groove in the the same purpose.

impellern Thev impeller is provided with i suitably shaped -vanes 6 located on one side 'impeller to receive the exit, so that the Mounted on the shaft.` is` Patented July 4, 1911.; Serial No. 404,058. i

lare provided which communicate with both sides of the impeller. It or they are made as close to the shaft axis as possible so as not to weaken the stock of which the parts are composed, and so that the rotation of the impeller will produce the minimum retarding effect on the passage of iiuid. It is necessary to provide a groove inthe hub of the key, and since this groove has to cut the fiber of the metal, it follows that to cut another groove or passage will not further weaken it to any material extent, providing the groove is not essentially deeper. Since the shaft is grooved to receive the key, it follows that it may also be grooved to form an equalizing passage without undue weakening. From this it will be seen that the weight of the' rotating element does not have to be increased nor the shaft enlarged to provide additional strengthto compensate for the passages. By

locating the grooves as shown, the wallsv have a relatively low surface speed, and hence the opposition to flow of the fiuid'is reduced to a minimum. The passageof the working Huid from the rear to the front of the impeller is facilitated if the groove is formed spirally, the radial height of the groove being less at the entrance than at the point of entrance will oppose slight resistance to the passage of the fluid, while the exit portion will exert a throwing e'ect at the point of discharge and a suctioneifect on the 'fluid column. This is shown at 13 in Fig. 3. In this illustration the groove extends in the direction opposite to that of rotation. For the same purpose, the generating lines ofv the groove` might be inclined forwardly at the entrance and rearwardly at the exit, and thus act as water-wheel or throwing buckets.

Figs. 1 and 4 representan impeller in which the entrance portion 14 of the hub groove is made low and the exit portion 15 made intentionally high so that the former offers but slight resistance to the entrance of Huid, and the latter exerts asuction' etfectl* As in Fig. 5, the radialfprolongation of the groove may be located in .a sleeve or spacer 16 placed against the impeller hub. This is useful where a number of impellers are" placed on the same shaft.

The above described .pressure-equalizing.

means can be employed for other purposes, as for example in turbine Wheels. 'I may also combine various features of the invention -in the same structure.

In accordance with the provisions of the patent statutes, I have described the principle of operation of with the apparatus which I now consider to represent the bestenibodiment thereof; but I def're to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, isf? 1. In an apparatus of the character described, the combination of a rotating element having a curved pressure-egualizing groove communicating with the hre' thereof and open at both ends, with a shaft that extends through the bore and supports the ele-r ment. l.

2. In an apparatus of the 'character described, the combination of a rotating element having a pressure-equalizing groove in the hub which has a greater radial depth on the discharge than on the inlet`side, With a shaft which carries theelement.

3. In an apparatus of the character described, the combination of a rotatingvelemy invention, together site nient having a pressureequalizing groove that opens into its bore and isinclined to the axis of the element With a shaft therefor which engages said bore and drives the element.

4. In an apparatus of the character described, the combination of a rotating element havin a spiral pressure-equalizing groove opening into its'bore, Witha shaft for supporting the element.

5. In an apparatus of the character described, the combination of a rotating element having a spiral pressure-equalizing groove in its-hub which extends in the oppodirection to that of its rotation, with a shaft for supporting the element.

G. In an apparatus of the character described, the combination of a rotating element having passage in its hub Which has an inlet thatJ is smaller than its outlet, with a shaft for sup porting and rotating the element.

In witness whereof, I have hereunto set my hand this 11th day of November, 1907.

HULDREICH KELLER.

a spiral pressure-equalizing i 

